Students project. Ins la Ferreria, Montcada i Reixac

1. A
AC
R AV
C CA
AR
M
Z,
DE
ILL
AN
E RN
LF
ST
O
RI
,O
AD
M
AR
M
U HA
M
L
R
AI
O
UM
Z,
S
E
QU
VAZ
NA
AN

2. INTRODUCTION
Did you know that water covers about 70% of the Earth?
But almost all of it is in the oceans and undrinkable.

3. INTRODUCTION
The solar still uses solar energy to purify water.

4. EQUIPMENT
Plastic Bowl Evaporating Dish Salt
Cling Film
A Beaker with
Food Dye Hot Water Small Stone

5. PROCEDURE
1st We add some food coloring and a teaspoon of salt.

6. PROCEDURE
2nd We then put the cup in the middle of the bowl.

7. PROCEDURE
3rd We add the hot water to the bowl until it is about one centimeter full.

8. PROCEDURE
4th Then we’ll cover the bowl loosely with cling film, sealing the film to the rim of the
bowl. You can use tape or string to do this if necessary.

9. PROCEDURE
5th Now we’ll take the equipment out to a sunny, level place.
6th Next we’re going to place the stone on top of the film, in the middle above the cup.
7th Now we’re ready to leave the still for at least an hour, the longer the better.

10. PROCEDURE
8th Then we’ll check to see if there is some water in the cup.
9th When we have some water in the cup, we’ll take the still back indoors and remove
the cling film.
10th Then we’ll take out the cup without splashing any water into or out of the cup.
11th Now we measure the amount of water in the cup and observe the color of the
water in it and test it for salt.

11. PROCEDURE
12th Here is how we then calculate the percentage of the water that was purified:
13th Lastly, we observe our results and see if we can explain what happened to the
water.

12. CONCLUSION
Now you may be wondering why it is called “purified water”. Well, what ideas do you
have? Tell me.

13. N
T IO
T EN
AT
U R
YO
FOR
KS
AN
TH